a class to access info from Twitter's "Sign in With Twitter" API. You can add additional methods as desired. See the conversation here: [http://css-tricks.com/forums/discussion/21825/output-value-of-nested-arrays]

twitter_user.php

<?php
/**
 * wraps info returned from twitter's "sign in with twitter" API.
 * add additional methods/properties as desired and use as a user class.
 *
 * @author Adrian Testa-Avila <github@custom-anything.com>
 * @copyright 2013 Adrian Testa-Avila
 * @license    creative commons attribution-sharealike
 *             http://creativecommons.org/licenses/by-sa/3.0/
 * 
 * @uses PHP 5.4+       For compatibility with v5.2+, 
 *                      see ## special instructions at|around line 42.
 */
class twitter_user{
    
##  NONPUBLIC PROPERTIES  ##

    /** 
     * object           this will hold the info you got from the twitter API. 
     *                  "protected" means it can't be accessed directly from outside the object
     *                   (e.g., like `echo $twitter_user->t`).
     *                  we do this so we can control how $t is accessed, using the __get() method below.
     */
    protected $t;
    
##  PUBLIC METHODS  ##

    /**
     * this method creates a new twitter_user object - 
     *  e.g., like `$chrisburton = new twitter_user( $twitter_array );`
     * it simply converts $twitter_array to an object and stores it in $this->t.
     * see the __get() method to see how you retrieve values.
     *
     * @param array $twitter_info   the info you got from twitter.
     */
    public function __construct( array $twitter_array ){
        if( !empty( $twitter_array['auth'] ) && is_array( $twitter_array['auth'] ) ){
            // you might want to verify other|all values exist,
            // beyond just ['auth'], but that's up to you.
            
            // converting the array into an object 
            //  makes it easier to access the values via our __get() method.
            // (using the json_* functions is an ugly hack, but works well.)
##  this works with PHP version 5.4.
##  v.5.3 does not support the json_encode flags used here (you can remove them).
##  v.5.2 does not support json_last_error (you can remove the error check and hope for the best.)
##  see comments on|around lines 51-62 below for alternate code if you need 5.2+ compatibility
##  (however, UPGRADING to 5.4+ is the recommended solution).
            $t = json_decode( 
                    json_encode( 
                        $twitter_array['auth']
##  PHP 5.3 compatability:
##  comment out the following line
                       ,JSON_BIGINT_AS_STRING|JSON_UNESCAPED_UNICODE 
                    ) 
                );
            // make sure there were no errors
##  PHP 5.2 compatability:
##  comment out the following line
            if( json_last_error() === JSON_ERROR_NONE ){
##  PHP 5.2 compatability:
##  un-comment the following line
//          if( true ){
                // all good.
                $this->t = $t;
            }else{
                // throw an exception so you know something went wrong
                throw new Exception( 'conversion to object failed' );
            }
        }else{
            // throw an exception so you know something went wrong
            throw new Exception( '$twitter_info is malformed' );
        }
    }

    /**
     * __get() is a "magic method" that runs 
     * whenever you try to access a nonpublic (or nonexistant) property.
     * we're going to use it to access the twitter array.
     * 
     * @param string $name     the name of the value asked for
     * @return mixed           the value that $name is mapped to, if it exists;
     *                         FALSE otherwise
     */
    public function __get( $name ){
        // first check if $name maps directly to a value in the twitter array:
        if( isset( $this->t->$name ) ){
            // this handles usage like `echo $chrisburton->uid;`
            return $this->t->$name;
        }
        // next, check if $name maps to a nested value:
        foreach( $this->t as $t ){
            if( isset( $t->$name ) ){
                // this handles usage like `echo $chrisburton->nickname;`
                // or even `echo $chrisburton->urls->twitter;`
                // (but *not* `echo $chrisburton->twitter;` - that won't work).
                return $t->$name;
            }
        }
        // finally, if nothing was found:
        return false;
    }
}

##  EXAMPLE USAGE  ##
/* (REMOVE everything that follows in production use) */

/** returned from twitter oauth API. */
$twitter_array = array(
    'auth' => array(
        'uid' => 0
       ,'info' => array(
            'name' => 'Chris Burton'
           ,'nickname' => 'chrisburton'
           ,'urls' => array(
                'twitter' => 'http://twitter.com/chrisburton'
               ,'website' => 'http://chrisburton.me'
               ,'dribble' => 'http://dribbble.com/chrisburton'
            )
           ,'location' => 'New York'
           ,'description' => 'Letterer & Typographer'
           ,'image' => 'http://a0.twimg.com/profile_images/3106804659/f100a994784f6e8059bb15125f286667_normal.png'
        )
       ,'credentials' => array(
            'token' => 'Token Removed'
           ,'secret' => 'Secret Removed'
        )
       ,'raw' => array(
            'id' => 0
           ,'profile_sidebar_fill_color' => 'DDEEF6'
           ,'created_at' => 'Thu Jun 25 22:48:35 +0000 2009'
           ,'contributors_enabled' => 0
        )
    )
 );

try{
    // create new twitter_user
    $cb = new twitter_user( $twitter_array );
}catch( Exception $e ){
    print $e->getMessage();
    exit;
}

// try it out:

// maps to `twitter_user->t->uid`
// outputs "0"
print $cb->uid;

// maps to `twitter_user->t->info->name`
// outputs "Chris Burton"
print $cb->name;

// maps to `twitter_user->t->urls->twitter`
// outputs "http://twitter.com/chrisburton"
print $cb->urls->twitter;